class_docstr: Chunks blocks into shuffled batches, using a local in-memory shuffle buffer.
docstr: Return shuffle buffer size.
docstr_tok: ["Return","shuffle","buffer","size","."]
code: def _buffer_size(self) -> int:
      """Return shuffle buffer size."""
      buffer_size = self._builder.num_rows()
      buffer_size += self._materialized_buffer_size()
      return buffer_size
  
imports: from typing import Optional
  from ray.data._internal.arrow_block import ArrowBlockAccessor
  from ray.data._internal.arrow_ops import transform_pyarrow
  from ray.data._internal.delegating_block_builder import DelegatingBlockBuilder
  from ray.data.block import Block, BlockAccessor
label_desc: Use image node_id 6 for calling the ShufflingBatcher obj's underlying member method code with example usage: obj._buffer_size() and returns: buffer_size